11.2% Efficient Solution Processed Kesterite Solar Cell with a Low Voltage Deficit

Graphical Abstract An 11.2% efficient kesterite solar cell is fabricated with a open circuit voltage (Voc ) deficit of only 0.57 V, which is possible by employing the three-stage annealing process. The reduced Voc deficit goes along with an increased minority carrier lifetime, low diode saturation current, and ideality factor, which are signatures of the semiconductor material with a low concentration of recombination centers.